.) - you should be OK but it would behoove you greatly to get some sort of documentation like a BPO (Broker Price Opinion) of the value now for use later in the refi!

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

If I'd know that I'd be paying it for the life of the loan I would have been better off paying the extra 5% down payment and enjoyed the lower interest rate but I don't recall ever being informed of that or reading it anywhere in my documents.

Also, you'll want to have legal documents drafted, specifically a mortgage lien, promissory note and some kind of JV agreement.

Security deposit amountYou can find plenty of examples by searching for "tenant estoppel certificate doc" or exchanging "doc" with "pdf" for more options.Here is an example and explanation: Sample EstoppelSome have a lot of legal jargon but this document does not need to be so detailed.

Closing costs on seller carried transaction are marginal, payments are collected and preferably administered by a third party and qualifying or documentation required is discretionary to the seller.

For this reason, it wouldnt make sense to rack up all the fees for title, escrow, lender fees, etc to do an investment cashout when you likely could get a personal loan at a similar interest rate, but only pay 300-500$ in document fees vice paying the 5-8K fees you'd likely rack up between the lender and title company with the refi. 

I have heard of keeping the 2 documents seperated, thank you for confirming that for me.

It costs $100 for a lease and several other documents written by investors and an attorney-approved for your state.

I think many of us use hyper-consumerism as a means of validating our self-worth.We NEED to upgrade to a new cell phone every year, we NEED to take expensive vacations to show our friends how fun our lives are, we NEED to purchase the more expensive car, we NEED to eat at chic restaurants and document the experience all over our social media.